Clamping mechanism



United States Patent 3,449,009 CLAMPING MECHANISM Donald M. Faust,Estacada, and Henry F. Chochrek, Portland, reg., assignors to CascadeCorporation, Portland, 0reg., a corporation of Oregon Filed June 9,1967, Ser. No. 645,027 Int. Cl. B66c 1/42, N62

US. Cl. 294-104 4 Claims ABSTRACT OF THE DISCLOSURE This inventionrelates to clamping mechanism, and more particularly, to such mechanismwhich may be used conveniently to clamp onto loads of widely differentsizes. For purposes of illustration only, and not with any intention tolimit other uses of the invention, the same as described herein relatesto a lift truck attachment for handling paper rolls and similar objects.

Clamping mechanism for handling paper rolls and the like typicallycomprises a frame, a pair of opposed, relatively movable arms mounted onthe frame for movement toward and away from one another, and clampingpads mounted adjacent the extremities of the arms which clamp againstthe sides of a roll.

Paper rolls may vary considerably in outside diameter. Thus, the arms ofsuch mechanism should be shiftable over a wide range, whereby they areable to encompass the many different sizes of rolls that are commonlyhandled. To obtain maximum stability for each size of roll that isclamped onto, the clamping pads should grip the roll as nearly aspossible on diametrically opposite sides of the roll. Any deviation fromdiametrical clamping should be minimal.

Paper rolls having relatively large diameters may, when clamped onto,extend into and occupy much of the region bounded by the frame and armsof the clamping mechanism. Accordingly, the mechanism should be sodesigned that this region is free of obstructions.

Since the mechanism may have to perform at times in confined spaces, theframe mounting the arms should have the smallest possible overalllength. Excessive length in any guide bars that sli'dably support an armshould be avoided, since such tend to project beyond the ends of themounting frame with the arms moved close together. It has been proposed,therefore, to provide an organization wherein at least one arm not onlytranslates but also pivots when brought toward the opposite arm. Thisinvention features an improvement in such an organization and the way inwhich such arm is pivoted while also translating toward the other arm.

Another factor to consider is that at times it is desirable to use thearms of the clamping mechanism backhandedly, i.e., as an agency formoving an object by moving the outer back side of an arm outwardlyagainst the object. To enable this type of operation, the mountings forthe arms should be such that they may be shifted outwardly under powerwhile held positively on the frame in the clamping mechanism.

3,449,009 Patented June 10, 1969 A general object of the presentinvention is to provide novel mechanism for clamping onto loads, such aspaper rolls, which takes care of the above considerations in a practicaland satisfactory manner.

More particularly, an object of the invention is to provide improvedclamping mechanism, including a frame and opposed relatively movablearms mounted on the frame, which can clamp onto the sides of loadshaving widely differing sizes.

Another object is to provide such mechanism, which is compact in size,which requires minimal space for movement of its arms, and whichprovides proper clearance for loads in the region bounded by the frameand arms.

According to the invention, the mechanism includes both a long arm and ashort arm, each carrying a clamping pad adjacent its outer extremity.Each arm is movable. With relative movement of the arms toward oneanother during clamping, the clamping pads come substantially againstdiametrically opposite sides of a load placed between the arms. With theusual sizes of loads that are handled, any deviation from exactdiametrical clamping is minimal. Toward this end, the long arm ismounted in such a manner that its outer extremity, with movement of thearm toward the short arm, moves in an arcuate path which firstsubstantially parallels and then is directed inwardly toward the framemechanism.

Characterizing a preferred embodiment of the invention, the long arm,intermediate its inner and outer ends, is pivoted to an arm base whichis mounted for movement along a substantially straight path on theframe. The inner extremity of the long arm is mounted on the framethrough novel link and pivot means, which affords arcuate movement ofsuch end about an axis spaced from the pivot axis provided by theconnection between the long arm and arm base. With such construction,during movement of the long arm, the clamping pad thereon travels alongthe above-mentioned arcuate path which, because of the link and pivotmeans, is somewhat straighter than a true circular path. Accordingly,within the full range of relative movement permitted the arms, theclamping pads tend to come against diametrically opposite sides of loadsplaced between the arms.

A further object of the invention is to provide such mounting structurefor the long arm which permits the arm to be used backhandedly whilepositively held.

These and other objects and advantages attained by the invention willbecome more fully apparent as the description which follows is read inconjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevation, illustrating the front portion of a lifttruck carriage on which is mounted clamping mechanism constructedaccording to the invention, such clamping mechanism including a pair ofclamping arms disposed one above the other with the clamping mechanismupright as shown; and

FIG. 2 is a view, partly in cross section, taken along the line 2-2 inFIG. 1.

Turning now to the drawings, indicated generally at 10 is load clampingmechanism taking the form of what is called a paper roll grab. Themechanism includes a pair of opposed relatively movable clamping arms,including a short arm 12 and a long arm 14 mounted on a frame 16 withthe arms extending out from the front of the frame. The mechanism ispositioned with arm 14 disposed above arm 12.

The rear of frame 16 is suitably attached to revolvable structure 18 ofconventional construction provided to enable rotation of the frame andarms about a substantially horizontal axis. In this'way the clampingmechanism may be used to upend a roll, or otherwise handle rolls restingon their ends or on their sides. Structure 18 includes a pair ofcircular, relatively rotatable plates 18a,

3 1815. A suitable power drive unit 20 is provided for rotating plate18b relative to plate 18a. Brackets 22a, 22b on the back of plate 18asecure structure 18 on an attaching plate 24 which is usually found onthe forward part of the elevatable carriage in a lift truck.

Frame 16 includes two pairs of elongated laterallyspaced tubes,comprising a first set of tubes or guides 28 and a second set of tubesor guides 30. As can be seen in FIG. 2, tubes 30 are positionedlaterally outwardly of tubes 28. Tubes 28, 30 have elongated slots 28a,3011, respectively, extending along their lengths. Slots 28a are locatedadjacent the upper ends of tubes 28 in the drawings, and open onto theforward sides and upper ends of the tubes. Slots 30a are locatedadjacent the lower ends of tubes 30, and open onto the forward sides andlower ends of the tubes. Tubes 28 are somewhat longer than tubes 30, andhave their upper ends extending upwardly beyond the upper ends of tubes30.

The upper ends of tubes 28 are secured together by an elongated endplate 32 which includes, adjacent its opposite ends, bores 32a receivingthe upper ends of the tubes. The plate has slots 32b which are alignedwith previously-mentioned slots 28a, and which extend from the frontedge of the plate into bores 32a. Between bores 32a, plate 32 furtherincludes an opening 320 and a bore 32d.

The lower ends of both pairs of tubes are secured together through anelongated end plate 34. Bores 34a in the plate receive the lower ends oftubes 30, and bores 34b receive the lower ends of tubes 28. Slots 34caligned with slots 30a, extend from the front edge of the plate intobores 34a. Between bores 34b the plate includes an opening 34d and abore 342, which are positioned directly oppostie previously-mentionedbore 32d and opening 320 respectively.

Turning to the construction of the arms, and considering first of allarm 12, the arm has a butt end 12a adjacent the frame and a tip end 1212located forwardly of the frame. In side outline, the arm tapersprogressing from the butt end toward the tip end. The arm comprisesouter and inner cover plates 36, 38 respectively. Adjacent the tip endof the arm, the cover plates are closely spaced, and progressing towardthe butt end the plates diverge and are joined to side plates such asside plate 40. Joined to the butt end of the arm and forming part ofwhat is referred to as an arm base is a back plate 42. Fastened to theback plate is a rearwardly projecting car 43 having a bore 43a.

Arm 12 is provided with a pressure pad 44 which is connected to the tipend of the arm through a hinge connection 46. The back edge of thepressure pad (the edge nearer frame 16) is urge-d toward the arm by asuitable biasing means indicated generally at 48 which interconnects thepad and arm.

Further describing the arm base which mounts arm 12 for movement alongthe frame, joined to back plate 42 are a pair of spaced-apart mountingmembers 50. Each mounting member includes a bar or slide portion 50aslid ably received within the interior of one of tubes 30, and a carrierportion 50b. Members 50, tubes 30 and slots 30a accommodate shifting ofarm 12 along a substantially straight path toward and away from arm 14.The slots in tubes 30 receive portions 50b with arm 12 moved inwardly onframe 12.

Considering arm 14, it includes, along each side thereof, a pair ofelongated, angular arm members 52 having the side profile illustrated inFIG. 1. Joined to the upper and lower faces of members 52 are coverplates 54, 56, respectively. The cover plates include forward endportions 54a, 56a which extend across the arm and are spaced closetogether to give a thin side profile to the forward end of the arm,central portions 54b, 56b which also extend across the arm and divergefrom one another progressing rearwardly along the arm, and inner rearend portions 540, 56c.

Arm 14 is provided with a pressure pad 58 which is similar to pad 44 onarm 12. Pad 58 is connected to the forward end of the arm through ahinge connection 60. Biasing means 62, which may be similar to biasingmeans 48, connects pad 58 to the arm, and urges the rear edge of the padtoward the arm.

Considering the mounting for arm 14 on the frame, an arm base for thearm is indicated generally at 64. Base 64 includes a pair of coverplates 66, 68 joined to side plates, such as side plate 70 (FIG. 1).Secured adjacent h outer ends of plates 70 are laterally-spaced bearings72 (FIG. 2). The inner ends of plates 66, 68, 70 are joined to anelongated back plate 74. A rearwardly projecting car 75 having a bore75a is secured to the back of back plate 74.

Arm base 64 further includes a pair of spaced-apart arm mounting members76 which are similar in construction to previously-described members 50.Thus, members 76 include bar or slide portions 76a slidably receivedwithin the interiors of tubes 28, and carrier portions 76b. The carrierportions are suitably joined to the back face of plate 74 adjacentopposite ends of the plate. Members 76, tubes 28 and slots 28aaccommodate translating of the arm base along a substantially straightpath between extended and retracted positions on the frame, toward andaway from arm 12. The slots in tubes 28 receive portions 76b with armbase 64 moved toward its retracted position on the frame.

Arm base 64 is connected to arm 14, intermediate the inner and outerends of the latter, through an elongated pivot pin or pivot means 78.Pin 78 extends through previously-mentioned bearings 72 in the armmember, through appropriate aligned bores provided in arm members 52,and through suitable bearings, such as those shown at 80 (FIG. 2),mounted on the arm in the space between end portions 540, 56c of plates54, 56. Pin 78 enables pivoting of arm 14 about an axis extendingtransversely of the arm.

Considering FIG. 2, suitably mounted adjacent the upper ends of tubes 30are lugs 82. The inner extremities of arm 14 are connected to these lugsthrough elongated links 84 and pivot pins, or journals, 86, 88. Pins 86connect one set of ends of links 84 to the inner ends of arm members 52on opposite sides of the frame. Pins 88 connect the other set of ends ofthe links to lugs 82. The respective pivot axes provided by pins 86, 88on either side of the frame are aligned.

Lugs 82, links 84, and pins 86, 88 comprise anchoring means for theinner extremities of arm 14. Such links and pins afiord restrictedarcuate movement of the inner extremities of the arm about the pivotaxis provided by pins 88. It will be noted that this axis is parallel tobut spaced from the pivot axis provided for the arm by pin 78.

Rams or power-operated means for shifting the arms toward and away fromeach other are shown at 90, 92. Considering ram 90, the cylinder of theram has a threaded axial projection 90a at its upper end in the drawingswhich extends upwardly through bore 32d in plate 32. The ram is mountedon plate 32 by means of a nut 94 screwed onto projection 90a. The rod ofthe ram extends downwardly through opening 34d in plate 34 and throughbore 43a in car 43. The lower end of the rod is secured to car 43 bymeans of fasteners 96.

Considering ram 92, the cylinder of the ram has a threaded axialprojection 92a at its lower end in the drawings which extends downwardlythrough bore 342 in plate 34. The ram is mounted on plate 34 by means ofa nut 98 which is screwed onto projection 92a. The rod of the ramextends upwardly through opening 32c in plate 32 and through bore 75a inear 75. The upper end of the rod is secured to ear 75 by fasteners 100.

Describing more fully the movement produceable in arm 14 with shiftingof arm base 64, such shifting causes pivot pin 78 to travel along asubstantially straight path, paralleling but disposed in front of tubes28. Movement of pin 78 causes the distance between the axis provided bythe pin, and the common axis of pins 88, to change.

Such changing of the distance between these two axes is accommodated andaccompanied by swinging of links 84 about pins 88. This, in turn,produces corresponding swinging of the inner extremities of the arm,where such are connected to the links through pins 86. Moreparticularly, swinging of the links produces arcuate movement of theinner ends of arm 14 about the pivot axis provided through pins 88. Themaximum arcuate movement of links 84 (and hence the inner extremities ofarm 14) required to accommodate shifting of arm base 64 from its fullyextended position to its fully retracted position, is illustrated asangle A in FIG. 1.

Further, with movement of arm base 64 from its extended to its retractedposition on the frame, it will be noted that the inner extremities ofarm 14 move first rearwardly and then forwardly relative to the framealong a substantially horizontal path, with such horizontal movementbeing accommodated by pivoting of links 84. As a consequence, theforward end of the arm travels along an arcuate path, such as thatindicated at P. Path P is not a true circular path, but is insteadflattened appreciably due to the movement just described produced in theinner extremities of arm 14. This feature of the invention enables theclamping pads on the arms, regardless of a loads diameter, to clamp ontoall loads substantially on diametrically opposite sides.

Explaining now how the clamping mechanism described may be used tohandle paper rolls of different diameters, in FIG. 1 several rolls areillustrated in dash-dot outline. At 102 is a relatively large roll; at104 a medium-sized roll; and at 106 a relatively small roll.

To grab any one of such rolls, the clamping arms, through operation oframs 90, 92, are shifted apart a sufficient distance to receive theroll, and are maneuvered whereby they are placed on substantiallyopposite sides of the roll. The rams are then operated to shift thepressure pads 44, 58 inwardly against the roll.

The positions of the arms required to clamp onto roll 102 aresubstantially those shown for the arms in solid outline; the positionsrequired to clamp onto roll 104 are shown in dash-dot outline at 12A,14A; and the positions required to clamp onto roll 106 are shown at 12B,14B. It will be noted that for each of the rolls illustrated, theclamping pads of the arms are disposed substantially on diametricallyopposite sides of the roll. As can be seen, any deviation from truediametrical clamping is minimal.

Thus, the mechanism provided herein can readily handle rolls having awide range of outside diameters, with nearly true diametrical clampingproduceable for each size roll. Only a minimal amount of space isrequired to accommodate movement of arms 12, 14. With guide tubes 28disposed inwardly of tubes 30 and having their upper ends extendingbeyond those of the latter, and with pivot parts 82 located as shown, arelatively compact, stable construction results.

It will be noted from FIG. 1 that the space bounded by the arms andframe is free of obstructions that might interfere with clamping of aroll. This space remains clear regardless of the positions of the armsand arm mountings.

With arm 14 mounted as shown, and mechanically linked at all times tothe frame, the arm can readily be employed backhandedly to push a loadto one side. Further explaining, let it be assumed that the clampingmechanism has been rotated by operation of revolvable structure 18 toshift the frame from the vertical position shown into a horizontalposition with the arms then being laterally spaced from each other infront of the lift truck. A roll or other object may then be shifted toone side through the expedient of extending arm 14 laterally outwardlywith cover plate 54 on the back side of the arm contacting the roll. Thearm will not give way during such an operation, since at all times, themounting for the arm functions to hold it in a predefined positionrelative to the arm base and frame.

While an embodiment of the invention has been described herein, it isappreciated thatvariations and modifications may be made withoutdeparting from the spirit of the invention. It is desired to cover allsuch variations and modifications that would be apparent to one skilledin the art and which come within the scope of the appended claims.

It is claimed and desired to secure by Letters Patent: 1. In clampingmechanism comprising a frame and a first arm mounted on and projectingforwardly of said frame,

an arm base on said frame occupying an extended position which is remotefrom said first arm, said arm base being mounted on said frame formovement toward said first arm along substantially a linear path toassume a retracted position on said frame,

another arm opposite the first arm projecting forwardly of said framehaving a rear end disposed adjacent the frame and a forward free end,pivot means mounting said other arm on said arm base at a point locatedbetween opposite ends of the other arm accommodating pivoting of saidother arm relative to the arm base about an axis extending transverselyof the other arm, said rear end of said other arm during movement of thearm base from its extended to its retracted position undergoing anoscillation by moving first rearwardly and then forwardly in a courseextending transversely of said linear path to effect flattenedcurvilinear movement in the free end of said other arm throughout suchmovement to a retracted position, and anchoring means anchoring saidrear end of said other arm on said frame throughout movement of the armbase from its extended to its retracted position generating suchoscillation in said rear end on movement of said other arm to itsretracted position and restricting movement of said rear end to movementalong said transverse course. 2. The clamping mechanism of claim 1,wherein said anchoring means anchoring said rear end of said other armon said frame comprises a link pivotally connected at spaced-apartpoints to said frame and to said other arm. 3. In clamping mechanismcomprising an elongated frame and a first arm mounted on said frameadjacent one of the frames ends and projecting forwardly of said frame,

an arm base mounted on said frame adjacent the other end of the framefor translational movement toward and away from said first arm,

another arm opposite the first arm projecting forwardly of said frameand having a rear end disposed adjacent the frame and a forward freeend,

pivot means mounting said other arm on said arm base at a point locatedbetween opposite ends of the other arm accommodating pivoting of saidother arm relative to the arm base about an axis extending transverselyof the other arm,

at least one link adjacent the side of the frame generally parallelingthe axis of the frame,

and spaced-apart journals connecting one end of said link to said frameand the other end of said link to said rear end of said other arm,respectively,

whereby the link serves as an anchor for said rear having a set of endsprojecting beyond a set of ends of said first pair of guides,

a first elongated arm projecting forwardly of said frame and an arm basesupporting said first arm for movement along a path on said first pairof guides,

a second elongated arm projecting forwardly of said frame, and an armbase for said second arm mounted for movement along a path on saidsecond pair of guides toward and away from said first arm,

pivot means mounting said second arm on its arm base 10 at a pointintermedate the second arms opposite ends, and anchoring means anchoringthe rear end of said second arm on said frame comprising a pair oflinks, each of which is pivotally connected at one location to said rearend, and at another location to said frame, said links being disposedlaterally outwardly of said projecting ends of said second pair ofguides and axially beyond said set of ends of said first pair of guides.

References Cited UNITED STATES PATENTS 3,008,596 11/1961 Oster 214-653FOREIGN PATENTS 900,720 7/1962 Great Britain.

RICHARD E. AEGERTER, Primary Examiner.

